Arthgal ap Dyfnwal

Arthgal ap Dyfnwal (804-872) was King of Alt Clut from 851 to 872, succeeding Dyfnwal ap Rhydderch and preceding Rhun ab Arthgal.

Biography
Arthgal ap Dyfnwal was born in 804, the son of Dyfnwal ap Rhydderch. He succeeded his father as King of Alt Clut in 851, and, in 870, the Vikings under Ivar the Boneless and Olaf the White besieged his capital of Dumbarton Rock. The Vikings captured the city and took many prisoners back to Ireland, and the kingdom relocated up the River Clyde, where it became known as the kingdom of Strathclyde. He was assassinated in 872 on the orders of the Pictish king Constantine I of Scotland.